Medium conveying apparatus and front loading mechanism

1. A medium conveying apparatus comprising: a hopper; a stacker; wherein any one of said hopper, said stacker and both said hopper and said stacker are of a drawer type having a drawer, wherein any one of said hopper and stacker receives a medium therein, and wherein any one of said hopper and stacker is loaded in an apparatus body of said apparatus, and a feed passage extending between said hopper and said stacker so that said medium is fed from said hopper into said feed passage and is discharged into said stacker; and a sensor means operative to detect any one of a presence and an absence of said medium in said feed passage at a boundary between any one of said hopper and said stacker and said apparatus body, so that when said presence of said medium in said feed passage is detected by said sensor means, a means for controlling controls opening and closing of said drawer of any one of said hopper, said stacker and both said hopper and said stacker, wherein said sensor means includes one sensor in any one of said hopper and stacker which is of said drawer type and another sensor in the feed passage adjacent to said hopper or stacker containing said sensor.

2. The medium conveying apparatus according to claim 1, further comprising a judging means receiving signals from each of said sensors for judging whether said medium is located at a boundary between said apparatus body and any one of said hopper and said stacker in accordance with a result detected by said sensors.

3. The medium conveying apparatus according to claim 2, further comprising: a locking portion which is driven by a drive means to engage with an engaging portion provided on any one of said hopper and stacker; and a controlling means operative to control said drive means in such a way that when said medium is located at said boundary of said apparatus body and any one of said hopper and stackers, as determined by said judging means, said locking portion will be engaged by said engaging portion.

4. The medium conveying apparatus according to claim 3, further comprising an unlocking switch means for disengaging said locking portion from said engaging portion, so that when said unlocking switch means is actuated, said controlling means drives said drive means to disengage said locking portion from said engaging portion.

5. The medium conveying apparatus according to claim 4, wherein when said absence of said medium in said feed passage is judged in accordance with said result detected by said sensors, said controlling means drives said drive means to disengage said locking portion from said engaging portion.

6. A medium conveying apparatus comprising: a hopper; a stacker; a front loading mechanism which includes a tray which can be retractably inserted in an apparatus body of said apparatus, said apparatus body including both said hopper and said stacker therein and any one of said hopper and said stacker including said tray; and a means for controlling opening and closing operations of said tray, wherein said controlling means includes an operator panel of said apparatus which is provided on a front surface of said tray and said operator panel has at least one operation button which can generate electric signals for said opening and closing operations of said tray.

7. A medium conveying apparatus comprising: a hopper; a stacker, wherein any one of said hopper, said stacker and both said hopper and stacker are of a drawer type having a drawer, wherein any one of said hopper and said stacker receives a medium therein, wherein any one of said hopper and said stacker is loaded in an apparatus body of said apparatus, so that said medium is fed from said hopper into a feed passage and is discharged into said stacker, such that opening and closing of any one of said hopper and said stacker is not allowed when said medium is present on said feed passage; a locking portion movably secured to said apparatus body and an engaging portion provided on any one of said hopper and said stacker, wherein said locking portion may engage with an engaging portion to allow closing of any one of said hopper and said stacker and may disengage said engaging portion to allow opening of any one of said hopper and said stacker; a feed roller supported by said apparatus body; a drive means provided in said drawer of any one of said hopper and said stacker for said feed roller as a drive source; and a power transmission switching means for both transmitting a drive force to said feed roller when said locking portion engages with said engaging portion and not transmitting said drive force to said feed roller when said locking portion disengages said engaging portion.

8. A medium conveying apparatus comprising: a hopper; a stacker, wherein any one of said hopper and said stacker is of a drawer type having a drawer, wherein any one of said hopper and said stacker receives therein a medium, wherein any one of said hopper and said stacker is loaded in an apparatus body of said apparatus, so that said medium is fed from said hopper onto a feed passage and is discharged into said stacker, such that opening or closing of any one of said hopper and said stacker is not allowed when said medium is present on said feed passage; a feed roller supported by said drawer; and a knob means for rotating said feed roller, wherein said knob means is connected to a shaft of said feed roller; and a one-way clutch by which said knob means is connected to said feed roller.

9. The medium conveying apparatus according to claim 8, wherein said one-way clutch is attached to a front end of said shaft of said knob means, a first gear is attached to said one-way clutch, and a second gear is attached to said shaft of said feed roller, such that said first and second gears mesh with each other.